1. Field of the Invention
The present invention relates to a self-aligning roller chocks, particularly those used in the barge industries.
2. Background Information
In the barge industry, individual barges are grouped in a barge train and are selectively coupled to towboats and docks. Wire and synthetic ropes are commonly utilized to couple the barges to each other and to the towboat and/or the dock. The reeving of the rope is known as the rigging. On the tow boat deck and/or the dock the rigging lines are often wrapped through a roller chock.
The patent literature discloses some examples of roller chocks such as an 1859 U.S. Pat. No. 24,810 entitled “Cleat”, U.S. Pat. No. 4,154,428 entitled “Adjustable Roller Chock”, U.S. Pat. No. 4,292,911 entitled “Roller Chock”, U.S. Pat. No. D253,161 entitled “Roller Chock”, and U.S. Pat. No. 6,640,738 entitled “Bitt with Rotatable Line-handling Surface”. These patents are incorporated herein by reference and represent an excellent background.
As barges are loaded and unloaded the level of the barge will vary causing significant changes in the angle on the barge coupled rigging lines. Vertical self-aligning roller chocks have been designed to accommodate various wire rope angles to the load, essentially providing vertical alignment. The existing vertical self-aligning roller chocks are helpful for face and wing wire rigging on barges as the sheave wheel and frame pivots up and down to accommodate both empty and loaded barges. Face rigging is generally rigging wire or rope from the head winches or capstans used to connect the towboat to the barges, while wing rigging are side coupling lines. The original vertical self-aligning roller chock designs were intended to result in reduced wear on both wire rope and sheaves and in addition to towboat decks, they maybe also useful on docks, terminals, and dredges. The existing vertical self-aligning roller chock is considered an upgrade over conventional roller chocks for barge related face wire and wing wire rigging, and commercial examples of such existing vertical self-aligning roller chocks are currently available from Wintech International, LLC of Louisiana.
The developers of the present invention have identified two shortcomings of the existing vertical self-aligning roller chock designs. The first is that the vertical self-alignment is hindered when used with synthetic line due to the light weight of the line. The second is that uneven loading on the existing vertical self-aligning roller chock can often create undue stresses and wear on the lugs and associated hinge pin(s) of the chock. It is an object of the present invention to address these deficiencies of the existing prior art.